JP2002093073A - Magnetic disk drive and flexible printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk drive which can effectively prevent a flexible printed board from twisting when it is bending and is highly reliable enough for regular use in high-temperature, high-humidity environment. SOLUTION: To increase the rigidity of both the width-directional end parts of the flexible printed board 13, the pattern width Wa of several data signal lines 23a at the width-directional end parts of the flexible printed board 13 in a group of data signal lines 23 for a magnetic head provided to the flexible printed board 13 is set equal to the pattern width Wb of a VCM line 21 and a GND line 22. Further, various elements, such as the pattern width, height, pitch, shape, material, etc., of each signal line on the flexible printed board 13, determining the rigidity are set axially symmetrical holding the width center of the flexible printed board 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic disk device such as a hard disk drive and a flexible printed circuit board used for the magnetic disk device.

[0002]

2. Description of the Related Art In a hard disk drive, a flexible printed board is frequently used for electrical connection between a head actuator and an internal printed board.

FIG. 3 shows an example of a flexible printed circuit board 51 used for this hard disk drive. In the flexible printed circuit board 51, the left portion 52 from the dotted line A is fixed to the head actuator by screws or the like, and the right portion 53 from the dotted line B is bent substantially at right angles and fixed to the internal printed circuit board by screws or the like. Have been.

[0004] The flexible printed board 51 repeats deformation as shown in FIG. 4 in accordance with the movement of the head actuator. In this example, when the inner peripheral portion of the disk 54 is accessed (b), the head actuator 55 interferes with the free portion of the flexible printed circuit board 51, so that a large deformation (bending) particularly occurs at the C portion of the flexible printed circuit board 51. ing.

The signal lines of the flexible printed board 51 include a VCM line 61 and a GND line 62 through which a drive current supplied to a VCM (voice coil motor) flows, and a data signal line 63 for a magnetic head. Usually, the optimum pattern width for these signal lines is determined by specifications according to the function. For example, the width of the VCM line 21 and the GND line 22 is about 0.3 mm, and the width of the data signal line 23 for the magnetic head is about 0.1 mm. In many cases, these signal lines are arranged collectively for each function, and the VCM line 21, the GND line 2
2 are usually arranged collectively at one end in the width direction of the flexible printed board 51.

[0006]

However, in such a flexible printed board 51, the difference between the pattern widths of the VCM line 21 (GND line 22) and the data signal line 23 at both ends in the width direction is caused by the difference in the pattern width. Of the flexible printed circuit board 5
The stress generated when the 1 is bent becomes non-uniform between both ends of the flexible printed circuit board 51 to cause twisting. Particularly in a high-temperature environment, microcracks tend to occur at locations where the stress due to the torsion concentrates, and in the worst case, there is a possibility of disconnection.

As a technique for preventing disconnection of a flexible printed circuit board, for example, Japanese Patent No. 26521 is disclosed.
No. 07. In this technique, dummy patterns not involved in electrical connection are arranged on both sides of a flexible printed circuit board for reinforcement.

However, even if the dummy pattern is added to a flexible printed circuit board having different signal line pattern widths on both sides, the difference in rigidity between the two sides of the flexible printed circuit board is not eliminated, and the flexible printed circuit board is not replaced. It is difficult to prevent twisting due to bending of the substrate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can effectively prevent torsion when a flexible printed circuit board is bent, and has reliability that can withstand normal use in a high-temperature, high-humidity environment. It is an object of the present invention to provide a magnetic disk device and a flexible printed circuit board with high performance.

[0010]

According to a first aspect of the present invention, there is provided a magnetic disk drive comprising: a head actuator for moving a magnetic head; a printed circuit board provided therein; And a flexible printed circuit board provided with a plurality of signal line patterns for electrically connecting the printed circuit board, and a pattern of one or more signal lines respectively arranged at both ends in the width direction of the flexible printed circuit board. The width is larger than the pattern width of the signal line arranged inside.

The present invention has such a configuration,
The rigidity of both ends in the width direction of the flexible printed circuit board is higher than that of the inner part, and it is possible to prevent the flexible printed circuit board from being twisted when bending due to the movement of the head / actuator. A highly reliable magnetic disk device that can withstand normal use can be realized. According to a second aspect of the present invention, there is provided a magnetic disk drive including a head actuator for moving a magnetic head, a printed circuit board provided therein, and a plurality of signal lines for electrically connecting the head actuator to the printed circuit board. And a flexible printed circuit board, wherein the pattern width of one or more signal lines respectively arranged at both ends in the width direction of the flexible printed circuit board is larger than the pattern width of the signal lines arranged inside thereof, and The signal line patterns at both ends in the width direction of the flexible printed board are provided symmetrically with respect to the center of the width of the flexible printed board.

According to the present invention, having such a structure, the rigidity of both ends in the width direction of the flexible printed board is higher than that of the inner portion, and the stress generated when the flexible printed board is bent is reduced. Becomes uniform between both ends in the width direction, and the effect of suppressing torsion can be further enhanced.

Further, a magnetic disk drive according to a third aspect of the present invention comprises:
A head actuator for moving a magnetic head, a motor for driving the head actuator, a printed circuit board provided therein, and at least a signal line for electrically connecting the head actuator to the printed circuit board. A flexible printed circuit board provided with a pattern of a power signal line of a motor and a data signal line of the magnetic head, wherein the pattern of the power signal line of the motor has one end in the width direction of the flexible printed board. Wherein the pattern width of the signal lines at both ends in the width direction of the flexible printed circuit board including the pattern of the power signal lines of the motor is larger than the pattern width of the signal lines arranged on the inner side thereof. I do.

According to the present invention having such a configuration, the rigidity of both ends in the width direction of the flexible printed board is higher than that of the inner part, and the flexible printed board is twisted when the flexible printed board is bent with the movement of the head actuator. And a highly reliable magnetic disk device that can withstand normal use in a high-temperature, high-humidity environment can be realized.

Further, a magnetic disk drive according to a fourth aspect of the present invention provides a head actuator for moving a magnetic head, a motor for driving the head actuator,
At least a pattern of a power signal line of the motor and a data signal line of the magnetic head are provided as signal lines for electrically connecting the printed board provided therein and the head actuator to the printed board. A flexible printed circuit board, wherein the pattern of the power signal line of the motor is disposed at one end in the width direction of the flexible printed circuit board, and the flexible printed circuit board includes the pattern of the power signal line of the motor. The pattern width of the signal lines at both ends in the width direction is larger than the pattern width of the signal lines arranged on the inner side thereof, and the signal line patterns at both ends in the width direction of the flexible printed board are aligned with the width center of the flexible printed board. It is characterized by being provided line-symmetrically with respect to it.

According to the present invention, having such a structure, the rigidity of both ends in the width direction of the flexible printed board is higher than that of the inner portion, and the stress generated when the flexible printed board is bent is reduced. Becomes uniform between both ends in the width direction, and the effect of suppressing torsion can be further enhanced.

In order to achieve the above object, a flexible printed circuit board according to a fifth aspect of the present invention is a flexible printed circuit board provided with a plurality of signal line patterns. The pattern width of one or more signal lines is larger than the pattern width of a signal line disposed inside.

According to the present invention, having such a configuration,
The rigidity of both ends in the width direction of the flexible printed board is higher than that of the inner part, and the occurrence of torsion when the flexible printed board is bent can be suppressed.

Further, according to a sixth aspect of the present invention, there is provided a flexible printed circuit board provided with a plurality of signal line patterns, wherein at least one signal line pattern is disposed at both ends in the width direction of the board. It is characterized in that the width is larger than the width of the pattern of the signal line arranged inside and the signal line patterns at both ends in the width direction are line-symmetric with respect to the center of the width of the substrate.

According to the present invention having such a configuration,
The stress generated when the flexible printed circuit board is bent becomes uniform between both ends in the width direction of the flexible printed circuit board, and the effect of suppressing torsion can be further enhanced.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a hard disk drive which is an embodiment according to the magnetic disk drive of the present invention.

As shown in FIG. 1, the hard disk drive 1 has two platters (fixed disks) 2, 3
Is a 2.5-inch hard disk array. The two platters 2 and 3 are attached to a drive shaft of a spindle motor (not shown) by a hub (not shown) and a clamper 4. The head actuator 15 is
A laminated carriage formed by stacking three head arm assemblies each composed of a suspension 6 supporting a magnetic head 5 such as a thin film head or an MR / GMR head at the tip and a thin plate arm 7 made of stainless steel, and rotatably supporting the laminated carriage. Bearing structure. The head actuator 15 is driven by a VCM (voice coil motor) 10.

The above structure is housed in a housing case 8, which is covered with an upper lid 9 to hermetically seal the inside. The upper lid 9 is fixed to the housing case 8 by screws 11. In order to increase the degree of sealing inside the storage case 8 covered with the upper cover 9, the storage case 8 and the upper cover 9 are closely contacted with a gasket (not shown) therebetween.

Further, the rear side of the housing case 8 has a DRA
M, a hard disk controller (HDC), a main printed circuit board on which a servo control circuit and the like are mounted are attached by screws or the like. The main printed circuit board is electrically connected to an internal printed circuit board 12 provided with a recording / reproducing preamplifier and the like, which is disposed inside the housing case 8. The actuator 15 is fixed to a portion of the laminated carriage by screws or the like.

FIG. 2 shows an example of the flexible printed circuit board 13 used in the hard disk drive 1. In the flexible printed circuit board 13, the left portion 16 from the dotted line A is fixed to the head actuator 15 by screws or the like, and the right portion 17 from the dotted line B is bent substantially at right angles to the internal printed circuit board 12 by screws or the like. Fixed.

The signal lines of the flexible printed board 13 include a VCM line 21 and a GND line 22, which are power signal lines for supplying a drive current for the VCM 10, and a plurality of data signal lines 23 for a magnetic head. Yes, VCM line 2
1 and the pattern of the GND line 22 are collectively arranged at one end in the width direction of the flexible printed circuit board 13, and the patterns of the plurality of data signal lines 23 for the magnetic head are also arranged collectively in other areas. .

According to specifications, the pattern width required for the VCM line 21 and the GND line 22 is equal to the data signal line 2 for the magnetic head.
3 is larger than the pattern width required, for example,
The required pattern width of the VCM line 21 and the GND line 22 is about 0.3 mm, and the required pattern width of the data signal line 23 for the magnetic head is about 0.1 mm.

In the present embodiment, in order to increase the rigidity of both ends in the width direction of the flexible printed board 13, the flexible printed board 13 of the group of data signal lines 23 for the magnetic head provided on the flexible printed board 13 is provided.
The pattern width Wa of some data signal lines 23a at the end in the width direction is set to be equal to the pattern width Wb of the VCM line 21 and the GND line 22.

As described above, the flexible printed circuit board 13
By making the rigidity of both ends in the width direction higher than that of the inner part, it is possible to prevent the flexible printed board 13 from being twisted when the head actuator 15 is bent, thereby preventing the flexible printed board 13 from being twisted in a high-temperature and high-humidity environment. A highly reliable hard disk drive that can withstand regular use can be realized.

Furthermore, in the hard disk drive 1 of this embodiment, at least various elements that determine the rigidity, such as the pattern width, height, pitch, shape, and material of each signal line in the bent portion 18 of the flexible printed circuit board 13 are defined by: By setting the flexible printed circuit board 13 to be line-symmetrical with respect to the width center of the flexible printed circuit board 13, the stress generated when the flexible printed circuit board 13 is bent becomes uniform between both ends of the flexible printed circuit board 13, thereby suppressing twisting. The effect can be further enhanced. For example, in the present embodiment, as shown in FIG. 2, the pattern width of a total of three signal lines of the VCM line 21 and the GND line 22 is about 0.3.
mm, among the group of data signal lines 23 for the magnetic head, only the three data signal lines 23a at the widthwise end of the flexible printed circuit board 13 have their pattern width, pitch, etc., as VCM line 21, GND line. 22 pattern width.

If the VCM line 21 and the GND line 22 have different pattern widths, the VCM line 21 and the G
Each data signal line 23 corresponding to the ND line 22 in line symmetry
Are equivalent to the VCM line 21 and the GND line 22
What is necessary is just to set each considerably. In the present embodiment, the case where the number of the VCM lines 21 is two and the number of the GND lines 22 is one has been described, but the present invention is not limited to such numerical conditions of the VCM lines 21 and the GND lines 22. . Further, in the present embodiment, the case where two VCM lines 21 and one GND line 22 are collectively arranged at one end in the width direction of the flexible printed circuit board 13 has been described. Is located at one end of the flexible printed circuit board 13 in the width direction, but the GND line 22
Even in the case where it is arranged away from the CM line 21, the pattern width of the data signal line 23 for the magnetic head may be set to be line-symmetric with respect to the center of the width of the flexible printed circuit board 3. .

By the way, for example, a 2.5-inch type hard disk drive includes a stacked type in which a plurality of fixed disks are stacked for large capacity, and a single-plate type in which one fixed disk is formed for low cost. These are manufactured using a common base, and the head and actuators are handled by changing the number of head arm assemblies to be stacked. Regarding flexible printed circuit boards, it is common practice to divert flexible printed circuit boards manufactured according to the specifications of laminated products to single-plate products. In this case, half of the data signal lines for the magnetic head on the flexible printed circuit board are used. Even in such a case, some data signals at the widthwise end of the flexible printed circuit board are used. VCM of signal line pattern width
, The rigidity of both sides of the flexible printed circuit board can be increased irrespective of whether the data signal line is functionally effective or invalid. Needless to say, it is possible to suppress torsion when the flexible printed board is bent.

[0034]

As described above, according to the magnetic disk drives of the first and third aspects, the rigidity of both ends in the width direction of the flexible printed circuit board is higher than that of the inner part, and the movement of the head actuator is reduced. With this, it is possible to suppress twisting when the flexible printed board is bent,
It is possible to prevent the occurrence of microcracks and disconnections in use in a high-temperature and high-humidity environment.

According to the magnetic disk drives of the second and fourth inventions, the stress generated when the flexible printed circuit board is bent can be made uniform between both ends in the width direction of the flexible printed circuit board. The deterrent effect can be further enhanced.

According to the flexible printed board of the fifth aspect, the rigidity at both ends in the width direction is higher than that at the inner part, and the occurrence of torsion when the flexible printed board is bent can be suppressed.

According to the flexible printed board of the sixth aspect, the stress generated when the flexible printed board is bent can be made uniform between both ends in the width direction of the flexible printed board, and the effect of suppressing twisting can be reduced. It can be even higher.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a hard disk drive which is an embodiment according to a magnetic disk drive of the present invention.

FIG. 2 is a diagram showing a configuration of a flexible printed board used in the hard disk drive of FIG.

FIG. 3 is a diagram illustrating a configuration of a conventional flexible printed circuit board.

FIG. 4 is a diagram showing a state of deformation of a flexible printed board in a hard disk drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hard disk drive 2, 3 platters 5 Magnetic head 12 Internal printed circuit board 13 Flexible printed circuit board 15 Head / actuator 21 VCM line 22 GND line 23 Data signal line

Continued on the front page F term (reference) 5D042 NA01 PA08 TA06 5D059 AA01 BA01 CA30 DA36 EA12 5D068 AA01 BB01 CC12 GG30 5E338 AA12 CC01 CC04 CC06 CD12 CD13 EE26

Claims (6)

[Claims] 1. A flexible device comprising: a head actuator for moving a magnetic head; a printed circuit board provided therein; and a plurality of signal line patterns for electrically connecting the head actuator and the printed circuit board. A printed circuit board, wherein a pattern width of one or more signal lines respectively arranged at both ends in a width direction of the flexible printed circuit board is larger than a pattern width of a signal line arranged inside thereof. Disk device. 2. A flexible printed circuit board provided with a head actuator for moving a magnetic head, a printed circuit board provided therein, and a plurality of signal lines for electrically connecting the head actuator and the printed circuit board. The pattern width of one or more signal lines respectively arranged at both ends in the width direction of the flexible printed board is larger than the pattern width of the signal lines arranged inside thereof, and the width of the flexible printed board A magnetic disk drive, wherein signal line patterns at both ends in the direction are provided line-symmetrically with respect to the width center of the flexible printed circuit board. 3. A head actuator for moving a magnetic head, a motor for driving the head actuator, a printed circuit board provided therein, and a signal for electrically connecting the head actuator to the printed circuit board. A flexible printed circuit board provided with at least a power signal line of the motor and a pattern of a data signal line of the magnetic head, wherein the pattern of the power signal line of the motor is in a width direction of the flexible printed circuit board. The pattern width of the signal line at both ends in the width direction of the flexible printed circuit board including the pattern of the power signal line of the motor, which is arranged at one end of the flexible printed circuit board, is larger than the pattern width of the signal line arranged inside thereof. A magnetic disk drive characterized by being large. 4. A head actuator for moving a magnetic head, a motor for driving the head actuator, a printed board provided therein, and a signal for electrically connecting the head actuator to the printed board. A flexible printed circuit board provided with at least a power signal line of the motor and a pattern of a data signal line of the magnetic head, wherein the pattern of the power signal line of the motor is in a width direction of the flexible printed circuit board. The pattern width of the signal line at both ends in the width direction of the flexible printed circuit board including the pattern of the power signal line of the motor, which is arranged at one end of the flexible printed circuit board, is larger than the pattern width of the signal line arranged inside thereof. The signal line patterns at both ends in the width direction of the flexible printed circuit board are large. Magnetic disk apparatus characterized by being arranged symmetrically across the width center of the flexible printed circuit board. 5. A flexible printed circuit board provided with a plurality of signal line patterns, wherein a signal width of one or more signal lines arranged at both ends in the width direction of the board is arranged inside the signal line. A flexible printed circuit board having a width larger than a line pattern width. 6. A flexible printed circuit board on which a plurality of signal line patterns are provided, wherein a signal width of one or more signal lines arranged at both ends in the width direction of the board is arranged inside the signal line. A flexible printed circuit board, wherein the signal line pattern is larger than the line pattern width and the signal line patterns at both ends in the width direction are provided symmetrically with respect to the center of the width of the board.